Gravitational field of global monopole within the Eddington-inspired Born-Infeld theory of gravity

TL;DR

This paper explores how the Eddington-inspired Born-Infeld gravity theory alters the gravitational field of a global monopole, affecting the spacetime structure, horizon size, and light deflection compared to standard models.

Contribution

It introduces a novel analysis of global monopoles within EiBI gravity, revealing unique features like a non-removable deficit angle and modified horizon and light deflection properties.

Findings

Deficit solid angle persists but cannot be transformed away unless EiBI coupling is zero.

Schwarzschild horizon shrinks with increasing EiBI coupling.

Light deflection angle decreases in the weak-field limit compared to the Barriola-Vilenkin solution.

Abstract

Within the framework of the recent Eddington-inspired Born-Infeld (EiBI) theory we study gravitational field around an $SO(3)$ global monopole. The solution also suffers from the deficit solid angle as in the Barriola-Vilenkin metric but shows a distinct feature that cannot be transformed away unless in the vanishing EiBI coupling constant, $\kappa$. When seen as a black hole eating up a global monopole, the corresponding Schwarzschild horizon is shrunk by $\kappa$. The deficit solid angle makes the space is globally not Euclidean, and to first order in $\kappa$ (weak-field limit) the deflection angle of light is smaller than its Barriola-Vilenkin counterpart.